Abstract:
CSMA based MAC protocols are known to incur throughput imbalance
when employed in multi hop wireless networks and existing
literature lacks efficient MAC protocol for wireless mesh networks.
Accurate modeling of interference and its affect on throughput
of flows in the WMN is critical in designing future wireless
networking protocols. This thesis performs a thorough analysis of
interference and capacity in wireless multi hop network based on
CSMA/CA MAC behavior. It is hypothesized that accurate modeling
of interference at MAC level can maximize overall network
capacity. In first part of thesis, twenty five unique possible two flow
topologies have been classified into six categories based on MAC
layer behavior and per flow throughput and closed form expressions
for occurrence probabilities of the identified categories have
been derived with particular observation that carrier sensing range
based categories have high occurrence probability and cannot be ignored.
MAC behavior of each category is discussed. In the second
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part, accurate computation of conditional packet loss probability and
busy time is done based on geometrical configuration of the interfering
links and also predicted per-flow throughput while addressing
CSMA’s coordination problem. Unlike previous work, our analytical
throughput model can clearly differentiate between links interfering
from transmission range and carrier sensing range. Analytical
and empirical results demonstrate improved accuracy, indicate
throughput imbalances and provide better understanding of CSMA
based protocol behavior in multi-hop wireless networks that can be
used to design fair, scalable, and efficient MAC layer protocols.
